Red Hat RHEV gets storage savvy

Red Hat RHEV 3.1 offers live migration and live snapshotting of virtual machines

By Joab Jackson | 05 December 12

Less than a year after a major update to its Red Hat Enterprise Virtualization (RHEL) package, Red Hat has upgraded the software to offer more advanced storage capabilities.

Released Wednesday, RHEV 3.1 allows administrators to make snapshots and clones of running virtual machines. And, in a technical preview mode, RHEV 3.1 supports storage migration for virtual machines (VMs), in which the backup disk image of a running VM can be moved from one SAN (storage area network) to another without stopping the running VM, said Chuck Dubuque, Red Hat product marketing senior manager for Red Hat virtualization infrastructure.

Storage live migration can be useful for several areas, Dubuque said. Live storage migration can be useful for balancing I/O across a system, or for those cases when a pool of VMs need to move from one SAN to another. In previous versions of the RHEV, such migrations would require the live running VM to be shut down while its disk image was being relocated. The live migration technology is available as a technology preview, until the release of the next version of Red Hat's flagship RHEL (Red Hat Enterprise Linux), which will provide the last bit of the needed functionality to fully execute live migrations.

With snapshots, RHEV can save a copy of a running VM for record-keeping purposes. And with cloning, RHEV can make a copy of a live VM that will also be operational. Previous versions of RHEV could only do snapshots and clones of a VM after that VM had been shut down. Snapshots are particularly valuable in development environments, in which the software being written must frequently be tested for bugs.

Dubuque noted that the KVM (Kernel Based Virtualization) hypervisor -- which is the open source foundation for RHEV -- has supported both snapshots and cloning, but noted that the functionality wasn't very robust. "Part of the value that Red Hat adds is hardening existing technology for enterprise use," he said.

Other new features have been added to RHEV 3.1 as well. One major enhancement is that now all the RHEV commands are available through the command line, which means that tasks can be automated through the writing of scripts. Red Hat even provides a Python SDK (software development kit) to help administrators write scripts. Support for Microsoft PowerShell is being developed by the RHEV open source community at Ovirt. The software VDI (virtual desktop infrastructure) now can support USB devices on remote clients. The software has also been integrated with Red Hat Storage Server, allowing an administrator to run both software packages from a single console. This version of RHEV also increases the total number of guest virtual machines each server can run. Now, up to 160 logical CPUs can be run on a single server, up from 64 in version 3.1. This number of logical CPUs is based on the largest server configuration that RHEL supports today, a server with 8 processor sockets, with each processor having 10 cores, and hyperthreading activated to run two threads per core. Paving the way for running RHEV on even larger servers tomorrow, Red Hat designed RHEV so that all 160 logical CPUs can be run from within a single VM. In addition to updating RHEV, Red Hat has revised a number of other software offerings as well. The company has released the first beta of the next version of RHEL. RHEL 6.4 comes with new advances in virtualization, file systems and identity management.

The company has also updated its CloudForms software for managing IaaS (infrastructure as a service) deployments. CloudForms 1.1 can now wok with LDAP (Lightweight Access Directory Protocol), which should allow organizations to use their current employee log-in credentials for cloud services.